Aharei Mot 

אחרי מות

There is no difference at all between commandments whose fulfillment is dictated by reason and the commandments that have no apparent logical rationale. Both are statutes of the Lord. 

The Sages taught: “You shall perform My ordinances” (Leviticus 18:4). These are matters that even had they not been written, logically they should have been written, and these are: idol worship, forbidden sexual relations, bloodshed, theft, and cursing God. “And My statutes you shall observe” (18:4). These are matters to which the accuser and the nations of the world object to their relevance, and these are: the prohibition against eating pork, the prohibition against wearing a mixture of wool and linen, the mitzva of freeing of a woman from her levirate bond to allow her to marry a man other than her late husband’s brother, the purification ritual of a leper, and the sending of the scapegoat sent to Mount Azazel on Yom Kippur and killed there to atone for the sins of the people. Lest you say: These mitzvot are meaningless, the verse states: “I am the Lord” (18:4). I, the Lord, legislated them, and you do not have the right to doubt them. <source>(<i>Yoma</i> 67b) </source>